Microbial iron transport agents, commonly known as siderophores, are of clinical importance as they provide an approach to the treatment of iron poisoning in humans by mediating solubilization and excretion of the metal. The main concern of the project is the structural characterization of such agents by means of nuclear magnetic resonance (NMR) spectroscopy so that more potent and specific drugs can be designed. Efforts are being done to isolate, purify, and characterize siderophore compounds produced by Pseudomonas fluorescens, reportedly, a bacterium that excretes ferribactin, a cyclic ferric decapeptide. Various NMR approaches have been investigated: (a) 27Al-NMR, as a probe to study metal-binding site symmetry; (b) proton double resonance experiments aimed at achieving a better analysis of peptide-siderophore NMR spectra; (c) crambin, a hydrophobic protein of MW 5000d, has been investigated at 250 MHz and 600 MHz, by using organic solvents to dissolve the protein. Membrane-bound siderophore receptors are supposed to contain hydrophobic portions.